Spot Measurement - Olympus Vanox AHBT3 Instructions Manual

D Special Applica tioj)
The special applications introduced here can help improve photo-
micrographic results under certain conditions.
Using the Exposure Adjustment Button D According to
Distribution of Specimen
Exposure can be adjusted using the exposure adjustment button
D
for a wide range of specimen contrast patterns: For example, dark field
observation or specimens where only small portions exhibit brightness;
or stained specimens, etc., where much background is removed. (Fig.
53)
• Specimen Conditions and Exposure Control with ISO/ASA 100 Film
Specimen conditions
Exposure
ISO/ASA
Exposure
adjustment value rating
variation
Specimen scattered in bright field
0.5 50 1 stop over
Specimen spread evenly throughout the field
1 100
Standard
Specimen scattered in dark field
2
200 1 stop under
Specimen scattered sporadically in darkfield
*4
400 2 stops under
.
The exposure adjustment button is adjustable in increments of 1/3
stop.
* If the adjustment range of the exposure adjustment button is
insufficient, adjust the ISO/ASA film speed.
,f Th.:''/
i'
-.,.
.:
Average
.1i.
t
.—
- 4t
•'
il
measure-
:1
jørnient; t
..
Exposure adjustment
Exposure adjustment
position "1
•'
position "4"
* Average measurement is performed in a central measurement
area with an 18 mm diameter on the 35 mm film, plane.
G
Spot Measurement
1
.
Press the spot measurement button D
and verify that the indicator
light above the button flashes. (Fig. 54)
2. Bring the specimen detail to be measured into the spot measurement
area; that is inside the reticle in the field of view.
* If the specimen detail to be measured cannot be photographed
inside the central measurement area, move it in the center for
exposure measurment only, engage the AE lock button, return
the specimen detail to its original position and initiate the exposure
(EXPOSE button). (See page 31 on how to use the AE lock
feature.)
Fig. 53
Exposure adjustment
position "0.5"
i T :
J
RECALL POWER
L
NO WINDING
SPOT
JECTIVJ
Fig. 54